1. Field of the Invention
Apparatuses and processes consistent with the present invention related to a process for the production of biodiesel in continuous mode without the use of a catalyst.
2. Description of the Related Art
Biodiesel is a potential substitute for diesel oil and consists of a mixture of fatty acids (methyl or ethyl) alkyl esters obtained from transesterification of vegetable oils with small chain alcohols (methanol or ethanol). In general terms, there are two routes which lead to a transesterification reaction: a catalytic and a non-catalytic route.
Within the catalytic route, there are processes with basic and/or acid catalysis (chemical catalysis) and enzyme employing processes (lipases) as catalysts (biocatalysts). Chemical catalysis (homogeneous or heterogeneous) has a long history of development and currently, biodiesel fuels produced by means of such methods are available in the market in some countries such as the United States, Japan, Australia and Western European countries. There are two basic disadvantages related to chemical catalysis produced biodiesel: during catalysis, the process is relatively slow and requires removal of the catalyst. Whereas during basic catalysis as well as purification of the catalyst product, the by-products of the saponification reaction must be removed. This process consists of the transesterification reaction, recovery of the non reacted alcohol, purification of the alkyl-esters and catalyst and separation of the glycerin from the reaction by-products. In such way, the process is unavoidably linked to high production costs and high power consumption.
Some of the disadvantages of the homogeneous chemical catalysis (product purification) may be overcome by using heterogeneous catalysts or enzymes as catalysts. Such processes are also costly due to the high cost of catalysts (heterogeneization of catalysts or enzymes). Likewise, in these processes, reaction time is longer still, since the reactions are produced with heterogeneous catalysts.
Recently, a process was disclosed in literature, which showed a non catalytic transesterification reaction in supercritical methanol (Saka and Kusdiana, Fuel, 2001, 80, 225-231; Saka and Kusdiana, Fuel, 2001, 80, 693-693; Kusdiana and Saka, Bioresource Technology, 2004, 91, 289-295). Reference is also made to US 2004/0,022,929; US2003/0,032,826; BR 0105888-6; U.S. Pat. No. 6,712,867; WO 03/22961; WO 2004/108873; U.S. Pat. No. 6,211,390; U.S. Pat. No. 6,174,501; U.S. Pat. No. 6,015,440; U.S. Pat. No. 5,525,126; U.S. Pat. No. 4,695,411; BR 0104107-0; BR 8300429-7; BR 8302341-0, as the state of the art.
It is noted that most of the disclosed processes in literature and patents are catalytic processes (homogeneous or heterogeneous chemical catalyzers and enzymes); they are processes which employ methanol as solvent and they are not continuous processes (bulk).